Pumps – Processes
Reexamination Certificate
2000-03-31
2001-11-20
Freay, Charles G. (Department: 3746)
Pumps
Processes
C417S048000, C417S050000
Reexamination Certificate
active
06318968
ABSTRACT:
TECHNICAL FIELD
The technical field of the invention is the dispensing of magnetorheological fluid to a magnetorheological device.
BACKGROUND OF THE INVENTION
Magnetorheological fluids that comprise suspensions of ferromagnetic particles such as iron or iron alloys in a fluid medium have flow characteristics that can change by several orders of magnitude within milliseconds when subjected to a suitable magnetic field due to suspension of the particles. The ferromagnetic particles remain suspended under the influence of magnetic fields and applied forces. Such magnetorheological fluids have been found to have desirable electro-magnetomechanical interactive properties for advantageous use in a variety of magnetorheological (MR) damping devices, such brakes, clutches, mounts and dampers.
Regardless of the type of device, the magnetorheological fluid must be loaded or injected into the device during manufacture. Magnetorheological fluids tend to be costly; and, depending on what additives are used for different applications, the release of such fluids to the environment might be undesirable. Thus, it is desirable to dispense precisely the correct volume of fluid to the device, with no spillage.
SUMMARY OF THE INVENTION
It is an object of the present invention, therefore, to provide a magnetorheological (MR) fluid dispensing device and system which effectively dispenses a predetermined amount of fluid for delivery to an MR device in a simple and cost effective manner. The MR fluid dispensing device and system disclosed is particularly, though not exclusively, adapted for a magnetorheological damper.
This and other objects of the present invention are achieved by providing a magnetorheological fluid pumping system for dispensing fluid for delivery to a magnetorheological device, comprising a pump including a bore, a piston mounted for reciprocal movement in the bore to form a pump chamber wherein the piston is movable through a retraction stroke to permit fluid flow into the pump chamber and a dispensing stroke to dispense fluid from the pump chamber. The pumping system also includes an outlet circuit for directing flow from the pump chamber and an outlet valve and/or an inlet valve. The outlet valve is positioned along the outlet circuit for controlling fluid flow from the pump chamber while the inlet valve is positioned to control fluid flow into the pump chamber. Both valves include an annular flow gap and a magnetic field generating assembly operable in an energized state to generate a magnetic field across the annular flow gap to cause magnetorheological fluid flowing through the gap to experience a magnetorheological effect sufficient to prevent flow through the gap and in a de-energized state to permit flow through the gap.
The pump may include a pump housing wherein the inlet valve and the outlet valve are mounted on the pump housing. The system may further include an electronic controller connected to the inlet and the outlet valves for controlling the energization and de-energization of the respective magnetic field generating assemblies. In addition, a stroke operator device may be provided to move the piston through the retraction and dispensing strokes. Also, the outlet valve may be positioned in axial alignment with a longitudinal stroke axis of the piston. In one embodiment, the inlet valve may be mounted on the piston. In this embodiment, the pump may include a pump inlet port at a first end and an outlet port at a second end opposite the first end with the outlet valve positioned adjacent the outlet port. In another embodiment, the pump may include a common feed chamber positioned at one end of the bore with the inlet and outlet valves positioned along the common feed chamber a spaced distance from one another. In this case, the bore extends transversely from the common feed chamber.
The present invention is also directed to a method of dispensing magnetorheological fluid for delivery to a magnetorheological device, comprising the steps of providing a pump including a bore and a piston mounted for reciprocal movement in the bore to form a pump chamber and reciprocating the piston through a retraction stroke to permit fluid flow into the pump chamber and a dispensing stroke to dispense fluid from the pump chamber. The method further includes the steps of providing an inlet valve to control fluid flow into the pump chamber wherein the inlet valve includes the gap and a magnetic field generating assembly operable in the energized and de-energized states and providing an outlet valve for controlling fluid flow from the pump chamber which also includes an annular flow gap and a magnetic field generating assembly operable in energized and de-energized states. The method further includes the steps of maintaining the outlet valve magnetic field generating assembly in the energized state and the inlet valve magnetic field generating assembly in the de-energized state during the retraction stroke of the piston. The method further includes the step of maintaining the outlet valve magnetic field generating assembly in the de-energized state and the inlet valve magnetic field generating assembly in the energized state during the dispensing stroke of the piston.
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patent: 6234060 (2001-05-01), Jolly
Kruckemeyer William Charles
Longhouse Richard Edward
Oliver Michael Leslie
Delphi Technologies Inc.
Freay Charles G.
Gray Michael K.
Sigler Robert M.
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